British Insects: the Families of Coleoptera
British Insects: the Families of Coleoptera |
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Clavigeridae, Staphylinidae.
General appearance. 1–3 mm long. Body length/maximum body width 1.5–10. Elytral length/pronotal length 0.9–2. Base of prothorax not or scarcely narrower than the combined elytral bases, or distinctly narrower than the combined elytral bases. Greatest prothoracic width not narrower or only slightly narrower than the greatest elytral width, or distinctly narrower than greatest elytral width. Beetles oval to elongate; conspicuously necked; somewhat waisted to conspicuously waisted; reddish or yellowish. Upper surfaces of body glabrous or subglabrous, or non-glabrous; not bristly; exhibiting scales or scale-like setae, or with neither scales nor scale-like setae.
Detailed morphology. Inclination of the head slight to strong. Eyes strongly protuberant, or not strongly protuberant; bristly, or without bristles; coarsely facetted. Ocelli present; paired. Antennae very short to long, but not exceeding the insect’s head to tail length; thick, (3–)5 segmented (commonly), or 6–10 segmented, or 11 segmented; clubbed. Antennal clubs 3 segmented. Antennal insertions visible from above, or hidden from above; ‘countersunk’ within saucer-like fossae, or not in fossae. Mandibular prosthecae present but reduced, or absent.
Prothorax about as long as wide. Pronotal length/maximum pronotal width 0.85–1.3. Prothorax at its widest markedly narrower than the adjoining part of the abdomen to not markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Metaventrite without a transverse groove. The tarsi with a tiny basal segment that is hard to detect, or without ‘hidden’ segments. Mid-leg tarsi 3-segmented; trimerous, or with fewer than three segments. Claws of the mid-leg tarsi not appendaged. Front tarsi with as many segments as the mid-tarsi; 3-segmented (or fewer). Hind tarsi with as many segments as the mid-tarsi; 3-segmented (or fewer). Tarsal claws simple; without an associated empodium. Elytral length/maximum width across the elytra 0.6–1.1. Elytra meeting along the length of the mid-line; short, exposing several terminal abdominal tergites (leaving most of the abdomen exposed, cf. Staphylinidae); exposing at least one but fewer than three complete abdominal tergites to at least three complete abdominal tergites; truncate. Scutellary striole absent. Wings well developed, or absent or much reduced.
Visible abdominal sternites 6–7; immovably joined 0. Abdominal segment 8 with apparently functional spiracles, or apparently without functional spiracles.
Habitat, ecology. Predacious; in decaying plant material, in rotting wood, under bark, on shed fur or feathers, and under stones (also in ants’ nests).
General comments. Readily distinguished from Staphylinidae by the dorsoventrally inflexible abdomen, and in having both the antennae and the palps clubbed.
Larvae. Larvae predacious; in decaying plant material, in rotting wood, in or under bark, in shed fur or feathers, and under stones (and in ants' nests).
Classification. Suborder Polyphaga; Superfamily Staphilinoidea.
British representation. Genera 19; 51 species. E.g., Bryaxis puncticollis (Punctured-necked Pselaphus); Trichonyx sulcicollis (Carlisle Pselaphus).
Illustrations. • Bryaxis puncticollis (Punctured-necked Pselaphus: B. Ent. 422). • Bryaxis puncticollis (details, B. Ent. 422). • Bryaxis puncticollis: B. Ent. 422, legend+text. • Trichonyx sulcicollis (Carlisle Pselaphus: B. Ent. 315).
To view the illustrations with detailed captions, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. British insects: the families of Coleoptera. Version: 9th June 2008. http://delta-intkey.com’.
